Apparatus and method of distributing pulverized coal in blast-furnace work



R. A. WAGSTAFF.

APPARATUS AND METHOD OF DISTRIBUTING PULVERIZED COAL IN BLAST FURNACEWORK., APPLICATION FILED 050.4, ms.

1 ,41 1 ,072, Patented Mar. 28, 1922.

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HOPPER FOE H/LVER/ZEDGUAL BLAST FURNACE AIR MAIN LOW PRESSURE i3 AIRLINE lfl-l/GH PRESSURE AIR' LINE 8 com.

suPPLv 17 HP INJECTOR TUYERE FLOOR L/IVE R. A. WAGSTAFF.

. APPARATUS AND METHOD OF DISTRIBUTING [EULVEBIZED COAL INBLAST FURNACEWORK.

APPLICATION mzomc. 4. 1919.

Patented Mar. 28, 1922.

UNITED STATES,

PATENT OFFIC E.

RICHARD A. WAGSTAFF, or SALT LAKE CITY, UTA afs'sIGfioR To SMELTING ANDREFINING COMPANY, OF

on NEW JERSEY.

NEW Yonx, N11, A coitromnon APPARATUS AND METHOD or DISTRIBUTINGreLvEmzEn count BLAST-FURNACE WORK;

Specification of Letters Patent. Patented Application filed December 4,1919.- Serial N6. 342,893.

To all whomz't may concern: I

Be it known that I, RICHARD A. WAG- STAFF, a citizen of theUnited-States,and resident of Salt Lake City, in the county of Salt Lakeand State of Utah, have invented certain new and useful Improvements inApparatus and Methods of Distributing Pul-' verized Coal inBlast-Furnace 'lVork, of which the following is aspecification- Theinvention relates to an improved method for preparinga carbonaceousfueland for feeding the same to a blastor other 'metallurgical furnace;andfthe invention further relates to an improved instrumen-' tality forpracticing the method.

It has been appreciated, heretofore that in certain metallurgicaloperations it is desirable to introduce fuel in a semi-gaseous'drycondition into a blast furnace for instance, by'pulverizin'g solid fueland feeding the. pulverized fuel .to the-injector twyers by means ofwhich the more or less diffused fuel was scattered into theinterior ofthe furnace. The air pressure on'the twyers, however, is usuall qulteh1gh,'due to the necessity of supplying sufficient oxygen-to sup-,

I of the invention is to provide a-preformed carbonized fuelcharacterized by the fact that each fine particle of carbonaceous particle is surrounded by an envelope of air and in which the body ofprepared fuel can be fed to the twyers in the manner in which the solidstream of pulverized. fuel has heretofore been fed to the twyers. Thepresent invention contemplates the economic formation-ofthe'carbonizedfuel which is further characterized by extreme minuteness of theparticle of the solid fuel and in'which the particles are uniformlyscattered in the air present. In other words, the invention features theformation of a nebulous cloud of.

carbonaceous material'which can be ejected i in this form into thefurnace byfhigh pres sure air.

Referring to the mechanical. features; of V the disclosure, one of theobjects of thisphase of the invention is to provide a sim leand'economically actuated device for. orming the peculiar character offuel'hereinbeforei outlined, and for maintaining the fuel in it diffusedcondition until itisdischarged into-the combustion zone of the furnace.

Another object of the invention featuring simpliclty of construct-ionand economyin operation is to provide such a device as'can be used as ian attachment to conventional V blast furnace plants; and which canutilize the sources of air pressures present in; con-.

ventional plantsv of this character.

Various other objects and advantages f of the invention will be in partobvious from .an inspection of the accompanying draw ings and in partwill be morefully set forthin the following particular description of'one form of mechanism embodying .myin- 'vention, and the invention alsoconsists in certain new and novel features of construction andCOIIlblIltLtlOIT of parts hereinafter set forth and claimed.

Referring to the accompanying drawings:

Figure 1 is a diagrammatierepresentation in elevation of a plantorganized to practice the method herein disclosed, but. it is to beunderstood that the elements illustrated are merely suggestive of oneperfected means for practicing the method;

Figures 2 to 4, inclusive, are enlarged detailed views of the coaldistributorshown in Figure 1; Figure 2 being a horizontal sectional viewtaken on the lines 22 of F igures 1 and 4; Figure 3- being a plan viewlooking down upon the coal distributor with its cover removed; andFigure 4 being a vertical sectional View taken axiallythrough" thedistributor and on the line 4-4 of Fig-. ure

Figures 5 and 6 are detailed views of one of the fuel dischargeoutlets-shown in F ig-- ures 2 and 4; Figure 5' being avhorizontalsectional view taken on the lines'5.5 of Figs. 4: and 6 and Figure 6being-an enlarged view in side elevation of the outlet,

shown partly in section. p

In the following description and in the claims, parts will be identifiedby specific charged in regulated amounts to a screwfeederll driven froma variable speed motor indicated symbolically by the driven belt 12ands'o timed as'to 'vea regulated feed of the more or less soli fuelstream er unit of time to the feed pipe 13 from which it is dischargedinto the combined fuel distributor and agitator 14.

The furnace supplied by the distributor is indicated at 15 and is of theconventional form, provided with a plurality of injector twyers 16equally spaced in a horizontal" plane about the furnace as is usualinsome "types of such structures. The furnaceis sup-. plied throughthe'twyers with air fromra suitable source of relatively low pressureair indicated symbolically by the air line 16' andat the air line there;is shown sym bolically a source of high pressureair.

Referring particularlyto Figure for a detailed description of thedistributor 14 it is noted that there isdisclosed' a cylindricalshellmember 18 having a flanged bottom, 19 which can be readily removed fromthe shell to permit access to the in terior' of thedistributor The shellis; pro

vided'With a horizontally disposed partition 20 which divides the"interior into a lower a'ir pressure chamber 21 and an upper, mixingchamber 22. This'partition is provided across its entire surface withequally'spaced and relatively small. holes 23 designed to cause the airpassing therethrough from the air chamber 21 to be evenly distributedthroughout the lower portion of the mixing chamber. Air under relativelylow pressure is introduced centrally through the bottom 19 by means of,a low pressure pipe 24 which leads from some suitable source of lowpressure air supply, such as the blast furnace air main 25. Aconeshaped' spreader 26 is disposed in themixing chamber; is spacedabove the partition and'is concentrically positioned below the dischargeend 27 of the feed pipe 13. The sides of the cone-spreader are inclinedbe yond the critical angle of the fuel fallingthereon and in the case ofpulverized coal this angle is made over sixty degrees declination. Thecone is provided with a discharging periphery 28 spaced from the innerside ofthe shell 18 so as to provide an annular passageway 29 for thefuel as it falls off the spreader towards the partition 20 in the formof a thin hollow cylinder." The cone spreader is supported centrally inthe shell by means of angle brackets 30." a V The top ofthe mixingchamber is closed by means of a semi-porous cover 31 which forms an airbleeding inlet permitting some leakage of atmospheric airfrom theoutside into the mixing chamber to agitate the fallingv fuel thereinwhile permitting the formation of a partial vacuum in the upper portionof the mixing chamber as hereinafter described. In the deviceillustrated the cover is made of a heavy grade of canvas which hasbeenfound to be acceptable under the pressure conditions present in thedevice herein disclosed.

A plurality of discharge conduits 31 lead from the lower port-ion ofthe. mixing ch'ambe'r to the furnace, one conduit for each of the twyers16. The intake ends of these conduits extend through the bottom 19,project above the'partition 20, are equally spaced apart in a circleconcentric with the axis of the shell and are disposed within the downwardly projected outline of the discharge periphery 28 of the conespreader. In the arrangement illustrated the intake ends are eight innumber and equally spaced in a circle,the radius of which is half theradius of theshell. The uniform spacing of themtake ends of the conduitsinsures'at'all times an equal withdrawal of the diffused fuel from allpartsof the inner periphery of the shell of fuel falling through theannular passageway 29. v

- For the purposeof insuring against the possibility of the fuelflooding into any one conduit and to assist in maintaining the fuel inits diffused condition the intake end of each of the conduits isprovided "with'a'plurality of apertures 32 spaced about the side of asleeve 33threadedinto the upper end of each of the conduits. The upperend of each of the sleeves is closed by a plug 34 which permits readyaccess'to sleeves in case the apertures 32 should become clogged.

The discharge end of each of the conduits 81 is connected to the outerend of. its corresponding twyer as shown in Figure 1, so

that the air pressure in line 17 acts to create,

a relatively high suction effect through the conduits 31. This highpressure tends to draw the carbonized fuel from the distributor to thetwyers and acts through the twyers to project the fuel forcefully intothe fur nace. It will be understood that the air pressures opened tothemixing chamber are such that the suction effect through the conduits31 will maintaina partial vacuum in the mixing chamber and that thepressure from the low pressure pipe 24 issufficient to maintain thefalling fuel in the state of suspension but is not sufficient in volumeto overcome the vacuum created in the mixing x chamber. It will beunderstood of course that the pressure and volume of the severalpneumatic pressureshereinbefore described, will be regulated by theoperator to fitthe peculiar condition present and for suchpurposessuitable control valves are provided.

In operation and assuming that a re ulated amount of the powdered coal,for in stance, is fed by the screw feeder 11 through the feed pipe 13and that the several air supplies are in active operation, the desiredform of carbonized fuel is fed uniformly into the furnace from all sidesthereof.

As the fuelfalls on the cone spreader it slides down the same, moving ina substantially uniform stream off the discharge'edge of the spreader.As the fuel attempts to fall towards the perforated partition or!diaphragm 20, it is met by the upcoming air which causes the particlesof the falling stream to separate'in the form of a cloud with theparticles held suspended in the mixing chamber. The carbonaceousmaterial remains in the mixing chamber'a ,sufiicient length of timetoinsure the maximum pos sible separation of the particles and thethorough mixing of the air into andbetween the separated particles These5 particles floating in the air medium will tend to obey the laws of gasdiffusion and-will flow in under the spreader from which po'sition'theyare picked up by the circle of fuel discharging intake ports andconveyed by a multiplicity of conduits'to'the different portions'ofthefurnace. a

By means of a deviceof the character outlined it is possible to form acharacter of carbonized fuel in which a regulated amount of the solidparticles are evenly distributed througha body of air and is which thedensity of the formed fuel is under the accurate control of theoperator. This carbonized fuel. with its desired density, is fed to thefurnace twyers and as there is an accurate "control of the air suppliedthrough the twyers there necessarily results that there will beintroduced into the furnace a regulated amount of fuel the thermal valueof which is accurately controlled.

Having thus described my invention, I claim:

1. In the art of preparing a fuel charge to be fed to a blast furnace,the method which consists in introducing a substantially solid stream ofthe pulverized fuel into a space having av pressure condition thereinless than atmospheric pressure, causing said streamxto spread out intoathin layer and while so spread out to fall freely in said space,subjecting the thin falling stream to the action of air under relativelylow pressure directed upwardly to hold the scattered fuel in suspensionand withdrawing the suspended mixture of air and fuel thus formed from aplurality of points by suction under relatively high pressure.

2. In the art of preparing a fuel charge to be 'fedto a blast furnace,the methodwhich consists in introducing a stream of 3. In the-art ofpreparing a fuel-charge to be fedto'a blast. furnace, the method whichconsists in introducing a stream of the pulverized, fuel into a spacehavinga pressure condition therein les's than atmos-,

'pheric pressure, causing said stream to spread out while-falling freelyin said-space,

subjecting the falling stream'to the action; of air under relatively lowpressure-directed upwardly to holdthe scattered fuel in suspension and'withdrawing the suspended mixture of air and fuel thus formed by suctionapplied to the space at a: plurality I of equally spaced apart pointsthereby toefi'ect'an even Withdrawal. of the mixture ency of themixturetobecomecondensed.

4. In the art'of mixing pulverized substance with air, the methodwhichr'consists in causing the substance to fall freely in the form of athin hollow cylinder into a mixing space havinga relatively low pressure condition therein,subjectingthe falling substance to the upwardlydirected action of air on opposite sides of the cylinder undera-pressure sufficient to break-{up the cylinder into fine particlesand-to keep the fine particles in suspension and withdrawing thediffused mixture of air and substance thus formed by a' suction effortunder a: pressure greater than the pressure o-f-the air admitted to thespace.

5. In the'art of mixing a pulverized substance with air, the methodwhich consists in causingthe substanceto fall freely in a thinstreaminto a mixing space having a relatively low-pressure conditiontherein, subjecting the v falling stream to the up wardlydirectedac'tion ofair under a pressure sufiicient to break up the streaminto fine particlesand to keep the particles in suspensionandwithdrawin'g thediffused mixture of air and substance thus formed-bya suction effort under a pressure" greater than the pressure of theair-admitted tothe space,'the suction action being divided anddistributed in the space to minimize the fromfthe space and torminimizeany tend- 1 relatively low pressure tov air chamber,

I so

flooding of the mixture into any one outlet and to prevent thecondensing of the mixturep 6. A combined agitator vand distributorprovided with aperforated partition forming an upper; mixing chamber anda lower air chamber, means for supplying air under relatively lowpressure to air chamber,

means for supplying a pulverized substance means for supplying apulverized substance to said mixing, chamber to meet the low pres sureair, directed upwardly through" said I. perforated partition, meanswithin the mixing chamber for spreadingthel substance introduced therebyto direct it evenly over the entire area" of the. upwardly-"mov ngair, asuction outlet from saidmixing chamber to withdraw themixtui e. of airand substance" from -:the;,mixing -:chamber,,.said' mixing;

chamberbeing closed. except for an'atmospheric ,airbleeding inlet' ofless intaking capacity than said suction efiectpresent whereby a partialvacuum is maintained in said mixing chamber.

- SLA. combined Iagitator and distributor 1 provided with a perforatedpartition form ing an upper mixin 'cha-mber anda lower.

air chamber, vmeans for supplyingair under relatively low, pressure toair chamber, means for supplying a pulverized substance to said mixingchamber to meet the low pressure air directed upwardly through saidperforated partition, a suction outlet from said mixing chamber towithdraw the mixture. of air and substance from the mixing chamber, saidmixing chamber bein closed.

except for'an atmosphericair blee ing inlet of' less intaking capacitythan said suction effectpresent whereby a partial vacuum is maintainedin said mixing chamber, said suction outlet provided with means tending,toobstruct the free discharge of the mixture from said mixing chamber.

9. In a device of the class described, a

cylindrical member having a closed bottom.

and an open top, a perforated partition for separating the interior ofthemember into an upper mixing-chamber anda lower air chamber, a semiporous cover for closing the open top while permitting a slight airleakage, means for introducing fuel through said cover and into saidmixing chamber, means disposed in said mixing chamber below saidintroducing means for spreading the fuel as it falls towards saidperforated partition, means for introducing air under pressure to saidair chamber in a volume sufficient to suspend said falling fuel in saidmixin chamber.

10. n a. device of the class described, a cylindrical member having aclosed bottom and an open top, a perforated partition for separating theinterior of the member into an upper mixing chamber and a lower airchamber, a semi-porous cover for closing the open top while permitting aslight air leakage, means for introducing fuel through said cover andinto saidmixing chamber, means disposedvin said mixing chamber below.said introducing means for spreading the fuel as it fallstowardssaid'perforated partition, means for introducing air underpressure to said air chamber in 'ayolume' s-ufiicient. to suspend saidfalling. fuel in said mixing chamber and an outlet. for the mixture ofairiand suspended fuel disposed beneath said spreadingmeans.

11. In a device'ofthe class and an opentop, a perforated partition Ydescribed,; a. cylindncal me'mber having aclosedlbottom forseparatingthe interior of the Inember into an upper mixing chamber and'alowerf air chamber, a semi-porous cover for closing the open top"while'lpermittinga'slight' air leakage," *means for introducing: .fuelthrough said cover and into-said mixing chamber, a conical spreaderhaving a fuel dischargingperiphery and a plurality 'of outlets for themixture of air and suspended fuel; said outlets being disposed inacircle below and within the projected outline of tne periphery of saidspreader and a receptacle for receiving the dischargefr'om all of saidoutlets. V I i 12. In a device of the class described, a cylindricalmember having a closed bottom and an open top, a perforated partitionfor separating the interior of the memberinto an upper mixing chamberand a lower air chamber, asemi-porous cover for closing the open topwhile permitting a slight air leakage, means for introducing fuelthrough said cover and into said mixing chamber, a conical spreaderhaving a fuel discharging periphery and a plurality of outletsfor themixture of air and suspended fuel, said outlet-s being disposed in acircle below and within the projected outline of the periphery ofvsaidspreader and a receptacle for receiving the discharge from all of saidoutlets, each of'said outlets provided with a plurality of intakes toassist in maintaining the fuel diffused in themixture.

13. In adevice of the class described,the

combination with a furnace, of means for feeding 'a mixture ofpulverized fuel and air to said furnace, said means including a sourceof fuel supply means for feeding a fuel stream in a regulated amount perunit of time from said source, a combined agitator and distributor forreceiving and scattering the fuel streams, means for diffusing airuniformly through said scattered fuel and for holding the same insuspension, a plurality of conduits having their intake ends spacedapart in said combined agitator and distributor so as to draw from allparts of the diffused fuel thereon and having their discharge endsspaced apart in said furnace and pneumatically actuated means forcausing the mixture of air and diffused fuel to pass through saidconduits and into said furnace.

14. In a device of the class described, the combination with a furnace,of means for feeding a mixture of pulverized fuel and air to saidfurnace, said means including a combined agitator and distributor forreceiving and scattering the fuel stream, means for diffusing air underpressure through said scattered fuel and for holding the same insuspension, a plurality of conduits having their intake ends spacedapart in said combined agitator and distributor and having theirdischarge ends spaced apart and opening into said furnace at a pluralityof points whereby the mixture of air and diffused fuel will beintroduced thereto. in a plurality of directions and pneumaticallyactuated means for causing the mixture of air and fuel to'pass throughsaid conduits and into said furnace.

15. In a device of the class described, the

' combination of a mixing chamber, means for introducing fuel so as tofall into said chamber, means for spreading the fuel as it falls towardsthe bottom of the chamber, means for directing air to move in an evendistribution upwardly through said bottom to meet the falling fuel andto hold the same in suspension diffused in the air and pneumaticallyactuated means for discharging the mixture of air and suspended fuelfrom said chamber.

16. In a device of the class described, the combination of a mixingchamber, means for introducing fuel so as to fall into said chamber,means for spreading the fuel as it,

falls towards the bottom of the chamber, means for directing air to movein an even distribution upwardly through said bottom to meet the fallingfuel and to hold the same in. suspension difi'usedin the air, meanspermitting a slight air leakage to said mixing chamber to permit apartial vacuum to form therein, suction means open to said chamber tomaintain said partial vacuum therein and to discharge the mixture of airand suspended fuel from said-chamber.

17. In a device of the class described, a mixing chamber havingmeansdefining the bottom thereof for diffusing air passed therethrough, meansfor causing pulverized fuel to fall freely through said chamber, meansfor passing air under pressure through said air diffusing bottomto acton the fuel and suspend the same diffused in the air present in thechamber, a semiporous cover for said chamber permitting an air leakagethereto, said chamber provided with a diffused fuel discharge port andpneumatic means acting through said port to withdraw thefuel from thechamber under a relatively low pressure condition.

18. In a device of the classdescribed, the combination with a furnacehaving a plurality of fuel intakes, injector twyers at each of saidintakes, of means for supplying said twyers equally and a mixture of airwith pulverized fuel diffused evenly throughout the air, said meansincluding a fuel distributor, means for feeding fuel to the distributor,means for causing air under relatively low pressure to be projectedevenly throughout the entire mass of the fuel and to hold the same insuspension in diffused condition,conduits leading from spaced apartpoints in said distributor to said twyers r thereby to draw from allparts of the same, and a source of relatively high pressure air suppliedto said twyers to drawv the fuel mixture from the distributor and toproject the same through the twyers and into the furnace.

19. In a device of the class described, the combination with a furnace,an injector twyer for introducing fuel under pressure to the furnace, ofmeans for supplying said twyer with a mixture of air having a pulverizedfuel diffused therein, said means including a distributor havingelements therein for subjecting a falling, thin stream of the pulverizedfuel to the action of a current of air under relatively low pressure anda source of air under relatively high pressure directed through saidtwyers for projecting the fuel into the furnace and for drawing thediffused fuel from the distributor and int the twyer.

Signed at Garfield in the county of Salt Lake and Stateof Utahthis 17thday of Nov. A. D. 1919. RICHARD A. WAGSTAFF.

